A variety of materials, including silage and haylage, are stored in tower silos. These materials range from the hard binding material and padded and interlocked fibrous material, to loose and light material. The different types of materials have different densities and hardness, making it difficult to efficiently remove the material from the silos. In the Winter season, the material adjacent the silo wall can become frozen to a hard mass.
Top unloading silo unloaders are used to remove the top layer of material from the silo and discharge the material into the silo chute. The top unloading silo unloaders have their greatest material removing efficiency when they are operated in a generally horizontal level position and moved around the silo wall at a substantially constant or even speed. Uneven material flow and large bunches of material reduce the capacity of the top unloading silo unloader and can plug the unloader. The top unloading silo unloaders have collectors that move around the silo walls to collect and convey material to an impeller which throws the material to an out chute and into the silo chute. Maintaining the collector in a selected operating position, as a horizontal level position, or at a slight angle, and driving the collector around the wall at an even speed is desirable to insure even feeding of the material to the impeller. This insures that a high volume of material can be efficiently handled by the unloader.